The present invention relates generally to safety restraint systems using airbags and particularly to a device and method of holding an airbag in a wrapped position. These devices must be strong enough to hold the deflated airbag in its initial position, yet weak enough to be easily broken, allowing the airbag to rapidly inflate.
Various restraining methods are used to package airbags in vehicles. When installed, an airbag is in a deflated posture, folded on top of itself, allowing for easy packaging in the airbag retainer. Various methods for restraining the airbag in its folded position are known in the industry. Some methods include covering the folded bag with a smaller, thinner bag, or wrapping the bag with a perforated paper cover or a woven fabric cover to wrap around the folded airbag. These methods are complex and expensive. Therefore, a simple, economical method of retaining an uninflated airbag in position is desired in the industry.
To reduce the complexity of such mechanisms, it is an object of the present invention to provide an improved method for supporting and restraining an uninflated airbag in the airbag retainer. The present invention utilizes a simple string as a restraint. The string material is preferably industrial sewing thread. The string is tied into a singular loop or an array of various loop types, depending on the size and shape of the particular airbag.
The uninflated, folded airbag is typically fastened to a base having at least one stud protruding therefrom. This stud is utilized to secure the airbag assembly to an airbag retainer. The string is looped over the stud in a first direction, looped around the airbag itself, then looped over the stud again from an opposing direction, thus securing the airbag in its folded position.
In the event of an accident, the airbag must rapidly inflate. It is therefore required that the string have sufficient tensile strength to retain the uninflated airbag in position during regular vehicle operation, yet break readily under stress to allow for proper deployment of the airbag during an accident.
Other uses and advantages of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications to the invention will be apparent to those of ordinary skill in the art from this detailed description.